If you use vim, you can do this within vim:

  :r !git log

find the log entry you're interested in, move the cursor over the sha1 value, type yiw to yank it into vim's " register (by default). Then open a new window by pressing ctrl-w n.

In that window run

  :r !git show <ctrl-r ">

where <ctrl-r "> will retrieve the sha1 value you yanked into the " register.

It's fewer steps, doesn't require using the mouse, and allows you to see both the git log output and git show output in different adjacent windows. You can always press u to undo the change in the new window, switch windows to get back to the git log output, find another sha1 and repeat the process.